• Journal of the Optical Society of Korea
• /
• 제5권3호
• /
• pp.99-109
• /
• 2001

This paper presents a phase-only modulation scheme for a three-dimensional (3-D) image matching system to improve optical efficiency of the system. The 3-D image matching system is based on the two mask heterodyne scanning. A hologram of the 3-D reference object is first created and then the phase of the hologram is extracted. The phase of the hologram is represented as one mask with the other mask being a plane wave. The superposition of each beam modulated by the two masks generated a scanning beam pattern. This beam pattern scans the 3-D target object to be recognized. The output of the scanning system gives out the correlation of the phase-only hologram of the reference object and the complex hologram of the target object. Since a hologram contains 3-D information of an object as a form of fringe pattern, the correlation of holograms matches whole 3-D aspect of the objects. Computer simulations are performed with additive gaussian noise and without noise for the complex hologram modulation scheme and the phase-only hologram modulation scheme. The computer simulation results show that the phase-only hologram modulation scheme improves the optical efficiency. Thus the system with the phase-only hologram modulation scheme is more robust than the system with the complex hologram modulation scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제4권6호
• /
• pp.1253-1272
• /
• 2010

In this paper, we propose a new affine shape adaptation scheme for the affine invariant feature detector, in which the convergence stability is still an opening problem. This paper examines the relation between the integration scale matrix of next iteration and the current second moment matrix and finds that the convergence stability of the method can be improved by adjusting the relation between the two matrices instead of keeping them always proportional as proposed by previous methods. By estimating and updating the shape of the integration kernel and differentiation kernel in each iteration based on the anisotropy of the current second moment matrix, we propose a coarse-to-fine affine shape adaptation scheme which is able to adjust the pace of convergence and enable the process to converge smoothly. The feature matching experiments demonstrate that the proposed approach obtains an improvement in convergence ratio and repeatability compared with the current schemes with relatively fixed integration kernel.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권3호
• /
• pp.1051-1077
• /
• 2021

The secure communication of information is a major concern over the internet. The information must be protected before transmitting over a communication channel to avoid security violations. In this paper, a new hybrid method called compressed encrypted data embedding (CEDE) is proposed. In CEDE, the secret information is first compressed with Lempel Ziv Welch (LZW) compression algorithm. Then, the compressed secret information is encrypted using the Advanced Encryption Standard (AES) symmetric block cipher. In the last step, the encrypted information is embedded into an image of size 512 × 512 pixels by using image steganography. In the steganographic technique, the compressed and encrypted secret data bits are divided into pairs of two bits and pixels of the cover image are also arranged in four pairs. The four pairs of secret data are compared with the respective four pairs of each cover pixel which leads to sixteen possibilities of matching in between secret data pairs and pairs of cover pixels. The least significant bits (LSBs) of current and imminent pixels are modified according to the matching case number. The proposed technique provides double-folded security and the results show that stego image carries a high capacity of secret data with adequate peak signal to noise ratio (PSNR) and lower mean square error (MSE) when compared with existing methods in the literature.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
• /
• pp.687-690
• /
• 1988

Algorithms that represent given pattern in the form of an ARG (Attributed relational graph) using not only structural relations but also symbolic or numerical attributes, and then recognize that pattern by graph matching process are presented in this paper. Based on definitions of pattern deformational models, algorithms that can find GPECI(Graph preserved error correcting isomorphism). SGECI(subgraph ECI) and DSECI(Double subgraph ECI) are proposed and comparisons among these algorithms are described. To be useful in performig practical tasks, efficient schemes for extraction of ARG representation fron raw image are needed. In this study, given patterns are restricted within objects having distinct skeleton, and then the information which is necessary for recognition and analysis is successfully extracted.

• International Journal of Internet, Broadcasting and Communication
• /
• 제7권2호
• /
• pp.149-154
• /
• 2015

Biometric techniques for authentication using body parts such as a fingerprint, face, iris, voice, finger-vein and also photoplethysmography have become increasingly important in the personal security field, including door access control, finance security, electronic passport, and mobile device. Finger-vein images are now used to human identification, however, difficulties in recognizing finger-vein images are caused by capturing under various conditions, such as different temperatures and illumination, and noise in the acquisition camera. The human photoplethysmography is also important signal for human identification. In this paper To increase the recognition rate, we develop camera based identification method by combining finger vein image and photoplethysmography signal. We use a compact CMOS camera with a penetrating infrared LED light source to acquire images of finger vein and photoplethysmography signal. In addition, we suggest a simple pattern matching method to reduce the calculation time for embedded environments. The experimental results show that our simple system has good results in terms of speed and accuracy for personal identification compared to the result of only finger vein images.

• Journal of the Korean Wood Science and Technology
• /
• 제37권6호
• /
• pp.556-565
• /
• 2009

제재목 육안등급판정 자동화시스템은 정확한 입력 화상이 요구된다. 이송 중인 재장 3.6 m의 국내산 소나무의 제재목 화상을 생성시키기 위해서 영역카메라를 이용하여 부분 화상을 획득하였고 2종류의 템플릿 위치지정법과 6가지의 템플릿 크기 조건을 적용하여 병합하였다. 특징영역 추출법이 템플릿 고정법에 비해 병합 성능이 우수하였다. 길이오차의 발생 요인은 명도차이, 특정 패턴, 템플릿 크기 등에 의한 유사도 하락에 있었다. 부정합은 길이가 길고 반복적인 목리에서 주로 발생하였다. 템플릿 크기는 6가지 템플릿 종류 중에 크기가 가장 작은 $100{\times}100$ 화소가 가장 병합 성능이 우수하였다. 병합 성능을 향상시키기 위해서는 정밀한 템플릿의 크기 선정과 명도 차이를 감소시킬 수 있는 화상병합 전처리에 대한 연구가 요구된다.

• 한국멀티미디어학회논문지
• /
• 제3권4호
• /
• pp.372-379
• /
• 2000

본 논문에서는 비트패턴을 기반으로 한 고속의 적응적 가변 블록 움직임 예측 알고리즘을 제안한다. 제안된 방법은 블록 내의 평균값을 기준으로 8bit 화소값을 0과 1의 비트패턴으로 변환한 후 블록의 움직임 예측을 수행한다. 비트변환을 통한 영상의 단순화는 움직임 추정의 계산적 부담을 감소시켜 빠른 탐색을 가능하게 한다. 그리고 블록 내의 움직임 정도를 미리 판별하여 이를 기반으로 한 적응적 탐색이 불필요한 탐색을 제거하고 움직임이 큰 블록에서는 정합 과정을 심화시켜 보다 빠르고 정확한 움직임 예측을 수행한다. 본 제안된 방식을 가지고 실험한 결과, 한 프레임 당 적은 수의 블록으로 고정된 크기의 블록을 가진 전역 탐색블록 정합 알고리즘(full search block matching algorithm; FS-BMA)보다 예측 에러를 적게 발생시켜 평균 0.5dB 정도의 PSNR 개선을 가져왔다.

• Journal of Information Processing Systems
• /
• 제15권4호
• /
• pp.737-747
• /
• 2019

Shape description is an important and fundamental issue in content-based image retrieval (CBIR), and a number of shape description methods have been reported in the literature. For shape description, both global information and local contour variations play important roles. In this paper a new included-angular ternary pattern (IATP) based shape descriptor is proposed for shape image retrieval. For each point on the shape contour, IATP is derived from its neighbor points, and IATP has good properties for shape description. IATP is intrinsically invariant to rotation, translation and scaling. To enhance the description capability, multiscale IATP histogram is presented to describe both local and global information of shape. Then multiscale IATP histogram is combined with included-angular histogram for efficient shape retrieval. In the matching stage, cosine distance is used to measure shape features' similarity. Image retrieval experiments are conducted on the standard MPEG-7 shape database and Swedish leaf database. And the shape image retrieval performance of the proposed method is compared with other shape descriptors using the standard evaluation method. The experimental results of shape retrieval indicate that the proposed method reaches higher precision at the same recall value compared with other description method.

• 한국컴퓨터정보학회논문지
• /
• 제12권1호
• /
• pp.57-65
• /
• 2007

서로 다른 형태와 크기를 가지는 탐색패턴과 움직임 벡터의 분포는 고속 블록 정합 알고리즘에서 탐색 속도와 화질을 좌우하는 중요한 요소이다. 본 논문에서는 새로운 고속 블록 정합 알고리즘 개발을 위해 기존의 다이아몬드패턴과 육각패턴의 단점을 해결할 수 있는 납작한 육각패턴을 제안한다. 제안하는 알고리즘은 움직임이 큰 벡터에 대해서 납작한 육각패턴을 이용하여 고속으로 움직임 벡터를 찾게 하였다. 실험 결과를 통해 제안된 납작한 육각패턴 탐색 알고리즘은 다이아몬드패턴 탐색 알고리즘이나 육각패턴 탐색 알고리즘에 비하여 움직임 벡터 추정의 속도에 있어서 약 $0.4{\sim}21.3%$의 성능 향상을 보였으며 화질 또한 PSNR 기준으로 약 $0.009{\sim}0.531dB$의 성능 향상을 보였다.

• 한국산학기술학회논문지
• /
• 제10권3호
• /
• pp.554-559
• /
• 2009

본 논문에서는 인쇄체 숫자를 인식하기 위해 가중 원형 정합(weighted template matching) 방법을 제안한다. 원형 정합은 입력 영상 전체를 하나의 전역적인 특징으로 처리하는 데 반해, 제안된 가중 원형 정합은 패턴의 특징이 나타나는 국부적인 영역에 해밍 거리(Hamming distance)의 가중치를 두어 패턴 특징을 강조하여 숫자 패턴의 인식률을 높인다. 실험에서는 기존의 원형 정합을 사용했을 때, 오류 역전파 신경망을 사용했을 때와 가중 원형 정합을 사용했을 때의 혼돈 행렬(confusion matrix)을 각각 서로 비교한다. 실험 결과는 본 논문에서 제안한 방법에 의해 인쇄체 숫자의 인식률이 크게 향상된 것을 보인다.